Drophead typewriter desk



Sept. 11, 1934. J. R. CLARK ET AL DROPHEAD TYPEWRITER DESK Filed Feb.29, 1932 4 Sheets-Sheet 2 IIII Hh 4 Sheets-Sheet 5' p 1934- J. R. CLARKEl AL DROPHEAD TYPEWRITER DESK Filed Feb. 29, 1952 P 1934- J. R. CLARKET AL, 4

DROPHEAD TYPEWRI'IER DESK Filed Feb. 29, 1932 4 Sheets-Sheet 4 ajayPatented Sept. 11, 1934 FFI'CE j 1,973,404 .DROPHEAD TYPEWRITER DESKJames R. Clark and Frederick 'W. Ackern ian, Rochester, N. Y., assignorsto Yawman' and Erbe Mfg. (30., of New York Rochester, N.Y., acorporation Application February 29, 1932, Serial No. 595,744

14 Claims. (01.:312 24) Our invention relates to drophead'typewriterdesks and is particularly concerned with the provision of improvedhardware" or mechanism for swinging the typewriter supporting shelf fromits 13 operable to its idle or storage position in conjunction with theopening and closing of the usual cover portion of the desk top.

A general object of our invention is to provide a four point suspensionfor the typewriter shelf 10 when in its operable position, to make .themounting for the typewriter more solidand free of vibration. It has beenfound that if the typewriter shelf is left free to vibrate, thetypewriterframe will be set in motion together with the shelf by theimpacts of the carriage Asa result the car riage is not always evenlyprogressed step by step under the influence of the carriage returnstrapand winding drum. The carriage mightbe released to movea space at a timewhich coincides 2'6 with the vibration of the typewriterfimovin'g in theopposite direction with the result that the momentum given the carriagecounteracts the spring tension on the carriage, and the following keyhits the paper before the carriage has been fully moved to its nextstop. Ithas also been foundthatthe keys which are mounted at the outerends of relatively flexible rods, are liable to be set in vibration bythe vibrating of the frame, with the result that they do not centeraccurate- .BG ly when they hit the paper or with the result they are sothrown out of their normal paths that theybind' with other type headsmoving into or out of position. i

It has been previously proposed to pivot the 35 front shelf near itsfront edgeeither by a fixed pivot or by a sliding pivot or itsequivalent in the form of guiding rollers-and pivotally toconnect theshelf near its rearward edge with an extension of the link whichcontrols the rearward edge of the cover. In such case the link and'itsextension constitute a beam which serves to swing the shelf between itsupper and lower positions by, and in accordance with, the movement ofthe cover. In some instances, instead ofproviding the sliding movementat'the forward pivot of the shelf, the necessary sliding has been"permitted by a slotted pivot of the beam to the rearward edge of theshelf.

We have discovered that an inherent objection to operating the shelf bythis beam which guides the rearward edge of the cover is that the swingmovement imparted to the cover is firs t fast, then slow, and then fast(assuming that the cover is moved at a uniform speed). This tends toslam the shelf'to its upper and lower positions.

On the other hand in those types of drophead actuating mechanismswherein the shelf is supported cantilever-wise from the front pivot, theoperating connection between the cover and the shelf is such as toimpart the more desirableclass of movement to the shelf-a movement whichis first slow, then fast, and then slow. This tends to ease the shelf,and the typewriter which it carries, into its upper and lower positions.The operating connection between the cantilever supported shelf and thecover is of varied types but most often comprises a toggle between thecantilever support of the shelf and the forward portion of the cover.The objection to the cantilever support however is that it is not assolid as a four point suspension.

' An object of our invention is to overcome these respective defects ofthese two types of mechanisms-while at thev same time retaining theirrespective advantages In general we accomplished this ,by retaining theusual cantilever type of suspension Withthe toggle between it andtheforward edge of the cover, to operate the shelf, that is, to swing itfrom its upper to its lower position. We also employ the extension onthe link, which guides the rearward edge of the cover, to provide arearward support for the shelf and thereby effect a four pointsuspension. But we do not employ the beam to operate the shelf. We bringit into positiononly ,to support the shelf.

Another object of our invention is to provide a truly effective fourpoint suspension which compensates for inaccuracies in the mechanism dueto manufacturing or assembly variations or to variations due to wear ofthe parts.

The foregoing, together with other objections, features, and advantagesof our invention are set forth in the following description of apreferred specific embodiment thereof which is illustrated in theaccompanying drawings wherein:

Fig. 1 is a perspective view of a typewriter desk showing the cover downand the shelf up; 7 Fig. 2 is a transverse vertical section through thedesk at its midpoint;

Fig. 3' is a section similar to Fig. 2 but showing the shelf down andthe cover up;

Fig. 4 is a perspective view of the operating mechanism alone, when thecover has been moved but a few inches upwardly from its down position ofFig. 2; v i

Fig. 5 is a front elevation of a fragment of the'desk shown in theposition of Fig. 1;

Fig. 6 is a vertical section taken on the line 66 of Fig. 3; r

Fig. 7 is a plan section taken on the line 7-7 of Fig. 2;

Fig. 8 is a vertical section taken on the line 8-8 of Figs. 5 and 7showing the cushioning pad between the frame and the shelf;

Fig. 9 is a vertical section taken on the line 9-9 of Fig. 2 through alateral edge of the shelf showing how the end of the beam supports therearward portion of the shelf; and

Fig. 10 is a view similar to Fig. 9 but showing.

a modified construction.

The desk here shown comprises similar left and right pedestals 15 and 16having inner walls 15a and 16a. The spaced pedestals are connected attheir backs by a back panel 1'7, across the rearward part of theirbottoms by the bottom panel 18 and on the tops by the connecting portion19a of the top 19. Forwardly of the connecting rear portion 19a, the topis cut away between the pedestals to receive the cover 20. At theirfront edges the pedestals are connected by a cross rail 21 of a wideU-shape. The legs of the U are secured to the adjacent corner legs ofthe pedestals, while the horizontal web of the U-shaped rail extendsjust below the depending front rail 22 of the cover 20, when the coveris in its closed position.

The cover is mounted to swing between a horizontal upper position (Fig.3) and a vertical lower position (Fig. 2). The mounting is effected by apair of links on each lateral side. One link 23 of the pair is pivotedat 24 to the under side of the top adjacent its forward edge, the otherend of the link being pivoted at 25 to a bracket 25 secured to the innerpanel 15a of the pedestal 15. The other link 26 of the pair is pivotedto the underside of the top 20 at 27 near its rear edge. The other endof the link26 is pivoted at 28 to the inner panel of the pedestal.

. At each lateral side, the shelf 30 carries a cantilever bracket 31which is pivoted at 32 to the inner panel of the pedestal and whichcarries an upwardly extending arm 33., Each arm 33 is pivotallyconnected by a link 34 with an extension 35 ,of the link 23, therebyforming a toggle. V 7

When the cover is in theopenposition of Fig. 2, the toggle isapproximately in its dead center position.

As'the forward edge of the top 20 is pulled upwardly and forwardly toits closed position, the link 23 swings through approximately 180, firstbreaking the toggle and then finally again bringing the pivots of thetoggle into approximate alinement, but with the toggle pivot proper atthe other side of the stationary pivot 25. This swinging of the link 23results in a general reciprocatory motion of the link 34 which swingsthe cantilever support .31 downwardly. Assuming a uniform arcuate speedof movement for the link 23, the pull imparted to the link 34, andconsequently the down swinging of the shelf 36, is first slow, thenfast. and again slow. This avoids jerking of the typewriter and easesthe typewriter and shelf into its lowermost position. The rear edge ofthe shelf 30 contacts the rail 18 at the'forward edge of the bottom wall18, when'the shelf is swung down to its lowermost position. By themechanism described, the

shelf comes gently to rest upon the rail 18' instead of violentlyimpacting it.

Similarly, when the cover is moved from its closed positionbf Fig. 3 toits open position of Fig. 2, the typewriter and shelf are not initiallyjerked upwardly, and. when they come to their uppermost position, theyapproach it gently.

Each link 26, which guides the rearward portion of the cover in itsmovement between its upper and lower positions, carries a bell crankextension 36. When in the position of Fig. 2, the extension 36 issubstantially vertical. At its free end the extension 36 carries aroller 37 which, when in the position of Fig. 2, engages a short channelshaped guide member 38 secured to the lateral edge of the shelf 30 nearits rearward edge. Inasmuch as the shelf is actuated by the toggles 34and 35, there being no connection between the bell crank extension 36and the shelf, the roller 37 very rapidly swings out of engagement withthe shelf-carried channel 38 when the cover 20 is swung upwardly fromits position in Fig. 2. As shown in Fig. 2, this is sobecause the firstfew inches of upward movement of the cover 20, acting through thetoggles, give but very little down swinging movement to the shelf whilea considerable movement is given to the bell crank extension.

Thus while the toggles serve at all times to position the shelf, thebell crank extensions'36 of the levers 26 function only when the shelfis substantially at its upper position. When the desk is in the positionof Fig. 3, the extensions 36 lie idle, having swung out of contact withthe channels 38. When the cover is lowered from its position of Fig. 3toward the position of Fig. 2, the extensions 36 swing upwardly tocontact their respective shelf-carried channels 38 after the toggles,actuated by the links 23, have swung the shelf substantially to ahorizontal position. The final arcuate movement of the bell crankextensions 36 is to cam the rearward edge of the shelf upwardly toitsfinal horizontal position.

Theoretically, the right and left pivots 32 and the right and left bellcrank extensions 36 provide a four point suspension for the shelf. Inpractice, manufacturing inaccuracies, inaccuracies of assembly, and wearof the parts would probably preclude an absolute four point suspension.Further, the-rearward portion of the shelf might rest upon the bellcrank extensions 36, rather than being firmly held against them. Thismight permit vibration also.

To remedy these objections, we introduce a resilient element at somepoint in the supporting mechanism. Preferably it consists in a pair ofrubber pads 39 clamped by bolts 40 to the underside of the shelf 30 nearits forward edge in such position that the pads are interposed betweenthe bottom of the shelf and the top flange of the front cross rail 21.The head of the bolt 40 may conveniently be set to clear the top flangeas shown in Fig. 8.

As the shelf is swung upwardly to its horizontal position, the forwardedge of the shelf swings downwardly toward the cross rail 21, becausethe pivots 32 are located rearwardly of the front edge of the shelf. Asthe shelf comes to its final horizontal position, the pads 39 areclamped between the shelf and rail. The final J swinging of the bellcrank extensions 36 acts with effective leverage to cam the rearwardedge of the shelf upwardly and thereby compress the resilient pads 39.Inasmuch as the upper toggles have come substantially to a dead centerrelation, at the end of the movement, substantially the entire weight ofthe cover 20 is utilized to swing the bell crank 26, 36, to effect thisfinal compression of the pads 39. One advantage gained is that the pads39 act as resilient stops to check a violent impact of the cover againstthe bottom wall 18.

The more important advantage however is that the resiliency of the padscompensates for any practical inaccuracies and permits a substantialfour point suspension of the typewriter shelf. It also holds therearward edge of the shelf tightly against the extensions 36, andotherwise prevents rattling or vibration.

The desk here shown is of sheet steel construction, although Icontemplate that the mechanism may also be applied to the usual wooddesk constructions. If the desk be of sheet steel construction, anupstanding wall 41 extending along the lateral andback sides of theshelf may conveniently be provided. As here shown the shelf top carriesdepending side flanges 42 and the wall 41 carries bottom flanges 43which extend inwardly beneath the flanges 42. The flanges 42 may bespot-welded to the walls 41 whereby the walls also serve to reinforcethe shelf. At the sides of the shelf, the wall 41 conceals the operatingtoggles which occupy the marrow space between the inner panels of thepedestals and the margins of the shelf. At the back of the shelf,thewall 41 serves to close up the opening between the shelf and thedepending front rail 22 of the cover when in the position of Fig. 2.

The cantilever brackets 31 may be secured to the lateral edges of theshelf by bolting them as at 44 to the bottom flanges 43 of the wall 41.nels 45 and 46 which preferably are located at or near the points wherethe front and back feet respectively, of the typewriter are to beclamped. As shown in Fig. 9, the cross channels preferably do not extendto the edges of the shelf, but only to the bottom flanges 43 of the wall41. This permits the use of a bottom plate 47 for the shelf withupturned lateral flanges 48, without the necessity of weakening thereinforcing effect of the flanges 48 by slotting them for the passage ofthe cross channels.

'In Fig. 10 we have illustrated a modification wherein outwardlyextending lateral channel 38 is dispensed with, and instead the roller3'? of the extension 36 bears directly against the underside of theshelf. A channel may be provided by beads 49 in the bottom flange 43 ofthe wall 41 to serve the purpose of the channel 38 in positioning theroller 37 against undue lateral movement. In Fig. 10 we have shown thecross channel 46 as extending to the lateral edge v of the shelf, andwith the flange 48 of the bottom supporting and guiding the cover from aforward horizontal closed position rearwardlyand downwardly to avertical open position, for pivotally mounting the shelf near itsforward edge to swing about a horizontal pivot, and, by interconnectionc with the cover, for swinging the shelf about its pivotal mounting froman upper horizontal position to a lower oblique position in conjunctionwith the closing of the cover, and other means actuated by the cover butnot contributing substantially to the swinging of the shelf for sup- Theshelf is further stiifened by cross shah-- porting the rearward portionof the shelf when the shelf is in its upper horizontal position.

2. A drophead typewriter desk comprising a desk body, a cover, atypewriter shelf, means for supporting and guiding the cover from aforward horizontal closed position rearwardly and downwardly to avertical open position, for pivotally mounting the shelf near itsforward edge to swing about a horizontal pivot, and, by interconnectionwith the cover, for swinging the shelf about its pivotal mounting froman upper horizontal position to a lower oblique position in conjunctionwith the closing of the cover, and means actuated by the cover but notoperatively connected with the shelf when the shelf is in its downswungposition for supporting the rearward portion of the shelf when the shelfis in its upper horizontal position.

3. A drophead typewriter desk comprising a desk body, a cover, a pair oflinks pivotally mounted on the desk body, one pivotally connected to thecover near its forward edge and the other pivotally connected to thecover near its rearward edge, for guiding and supporting the cover froma closed horizontal position downwardly and rearwardly to a verticalopen position, a typewriter shelf, means for pivotally mounting thetypewriter shelf on the body near the forward edge of the shelf, meansincluding said first mentioned link for swinging the shelf between anupper horizontal position and a lower oblique position and meansnormally operatively independent of the shelf for supportingly engagingthe rearward portion of the shelf when the shelf is in its upperhorizontal position.

4. A drophead typewriter desk comprising a desk body, a cover, a pair oflinks pivotally mounted on the desk body, one pivot-ally connected tothe cover near its forward edge and the. other pivotally connected tothe cover near its rearward edge, for guiding and supporting the coverfrom a closed horizontal position downwardly and rearwardly to avertical open position, a typewriter shelf, means for pivotally mountingthe typewriter shelf on the body near h the forward edge of the shelf,means including said first mentioned link for swinging the shelf betweenan upper horizontal position and a lower oblique position, and anextension on the second mentioned link normally operativelysindependentof the shelf but adapted to support ingly engage the rearward portion ofthe shelf when the shelf is in its upper horizontal position.

5. A drophead typewriter desk comprising a desk body, a cover, a pair oflinks pivotally mounted on the desk body, one pivotally connected to thecover near its forward edge and the other pivotally connected to thecover near its rearward edge, for guiding and supporting the cover froma closed horizontal position downwardly and rearwardly to a verticalopen position, a typewriter shelf, means for pivotally mounting thetypewriter shelf on the body near the forward edge of the shelf, meansincluding said first mentioned link for swinging the shelf between anupper horizontal position and'a lower oblique position, and an extensionof said second mentioned link constituting therewith a bell crank, saidextension being operatively independent of the shelf when the shelf isin its desk body, a cover, a pair of links pivotally mounted on the deskbody, one pivotally connected to the cover near its forward edge and theother pivotally connected to the cover near its rearward edge, forguiding and supporting the cover from a closed horizontal positiondownwardly and rearwardly to a vertical open position, a typewritershelf, means for pivotally mounting the typewriter shelf on the bodynear the forward edge of the shelf, and means including said firstmentioned link for swinging the shelf between an upper horizontalposition and a lower oblique position, said second mentioned linkextending on the opposite side from its pivotal mounting on the desk andconstituting with the link a beam, said extension supportingly engagingthe rearward portion of the shelf to support the shelf when in itshorizontal position.

7. A drophead typewriter desk comprising a desk body, a cover, means forsupporting and guiding the cover from an upper horizontal closedposition downwardly and rearwardly to a vertical open position, atypewriter shelf pivotally mounted at its forward edge, mechanismactuated by movement of the cover for swinging the shelf between anupper horizontal position and a lower oblique position, said mechanismswinging the shelf with a movement which is, in reference to themovement of the cover, first slow, then fast, andthen slow, said coverguiding and supporting mechanism including a link pivotally mounted onthe body and pivotally connected to the rearward portion of the cover,an extension of said link constituting therewith a bell crank, whichextension is swung with a movement which is first relatively slow, thenfaster, said extension engaging the shelf to support its rear portionwhen the shelf swung to its upper position.

8. A drophead typewriter desk comprising a desk body, a cover, a pair oflinks for supporting and guiding the cover from an upper horizontalclosed position downwardly and rearwardly to a vertical open position,each link being pivotally mounted at one end on the body, the other endsof the links being pivotally connected respectively to forward and rearportions of the cover, a typewriter shelf, means for mounting the shelfon the body to swing about its forward portion from a horizontal upperposition to an oblique lower position, an extension on the forward linkconstituting a toggle lever, a toggle link connecting the extension withthe forward portion of the shelf for swinging the shelf by the movementof the cover, an extension of the rearward link constituting therewith abell crank, said extension being normally operatively independent of theswinging of the shelf but engaging the shelf when the shelf is in itsupper position, for supporting its rearward portion.

9. The combination with a desk, of a typewriter shelf pivotally mountednear its forward portion on the desk to swing upwardly from a lowerposition to an upper horizontal position, a cushioning member spacedfrom said pivotal mounting for resiliently limiting the upward swingingof the shelf to its final upper position, and shelf operating mechanismremoved from said pivotal mounting and said cushioning member forswinging the shelf to its final position against the cushioning memberand for lockingly clamping the shelf against the cushioning member withthe latter under resilient compression whereby the cushion member reactsupon the mechanism, urging the shelf in the opposite direction of swing.

10. A drophead typewriter desk comprising a desk body, a cover mountedto move from a closed horizontal position rearwardly and downwardly toan open vertical position, a typewriter shelf mounted to swing about itsforward portion from an upper horizontal position to a lower obliqueposition, mechanism interconnecting the shelf and cover to swing theshelf by movement of the cover, resilient means tending to limit thefinal upward swinging of the shelf, and other means connected with thecover and actuated by its movement for swinging the shelf into its finalupper position against said resilient means.

11. A drophead typewriter desk comprising a desk body, a cover mountedfor movement from a horizontal closed position downwardly and rearwardlyto an open vertical position, a typewriter shelf, means for pivotallymounting the shelf at its forward portion but rearwardly of its forwardedge, mechanism interconnecting the shelf and cover for swinging theshelf between an upper horizontal position and a lower oblique positionby the movement of the cover, a cross rail mounted on the desk body andextending beneath the shelf forwardly of its pivotal mounting, aresilient member interposed between the shelf and the cross rail, andother mechanism connected with the cover and actuated by the movementthereof for operatively engaging the shelf to force the shelf into itsfinal upward position against the force of said resilient member.

12. A typewriter desk comprising a desk body, a rectangular shelf, acover, and means affording a four point suspension of the shelf from thedesk body comprising, at each lateral side of the shelf, a pivotalmounting for the shelf near its forward portion, cover actuatedmechanism engaging the shelf near its rearward portion for forcing therearward portion of the shelf to its final horizontal position, and aresilient mem-' ber forward of the pivotal mounting for the shelf,interposed between the shelf and the body and compressed by said forcingaction on the cover for compensating for any practical inaccuracies in atheoretical four point suspension and for holding the shelf againstvibration said mechanism locking the shelf against the resilient memberwhen thus compressed.

13. A typewriter desk comprising a desk body, a typewriter'shelf, meansfor pivotally mounting the shelf adjacent its forward portion to swingfrom an upper horizontal position to a lower oblique position, a cover,means interconnecting the cover and the shelf to swing the shelf betweenits two, positions, channel brackets at the lateral sides of the shelfat its rearward portion, and pivotally mounted levers also connectedwith and operated by movement of the cover having rollers at their freeends, adapted to engage said channels to support the rearward portion ofthe shelf when the shelf is in its upper horizontal position.

14. A drophead typewriter desk according to claim 13, wherein thechannels are mounted be yond the lateral edges of the shelf.

JAMES R. CLARK. FREDERICK W. ACKERMAN.

